Netherlocks has introduced Trapped Key Interlocking to eliminate human error. It is designed to guide the operator step by step while he operates valves, switches or doors that belong to critical procedures such as pressure valve changeover, pump start-up, etc. The Netherlocks Trapped Key Interlocking devices are mounted to the host equipment in such a way that they become an integral part of it. The only extra step an operator has to make is to slide a uniquely coded key blade into the lock body. If the blade fits properly it unlocks the valve and this subsequently proves that the operator has started with the proper device within his sequential operation. After operating the locks the initial inserted key will be trapped, while a second key can be released once the valve has been operated to the final position. Releasing the second key assures that the valve has reached the proper position and that it is blocked against unauthorised operation. It is easy to understand that such a system is foolproof and requires no supervision. Trapped Key Interlocks are widely used in the chemical, petrochemical, offshore and machine-guarding industry to guarantee a proper sequence and to eliminate human error.
